Ductile Damage Model for Predicting Crack Growth in Structural Component Subjected to Large Cyclic Deformation

The purpose of this study is to develop a ductile damage model for predicting ductile crack growth behavior of structural component subjected to large cyclic deformation.Work hardening rule with isotropic hardening stagnation is proposed based on the effective damage concept proposed by the authors.Damage evolution rule with damage acceleration under tensile straining and no damage acceleration under compressive straining just before fracture is also proposed.The ductile damage model for monotonic loading proposed by the authors is extended for cyclic loading by introducing the proposed work hardening rule and the damage evolution rule.The proposed work hardening rule can predict not only Bauschinger effect but also work hardening stagnation and permanent softening behavior with no additional parameters from conventional isotropic / kinematic combined hardening rule.Ductile crack growth predicted by simulation based on the ductile damage model with conventional damage evolution rule is larger than experimental results.On the other hand, simulation based on the ductile damage model with the proposed damage evolution rule can predict ductile crack growth behavior and load carrying capacity under not only constant but also variable strain amplitude.Consequently, the proposed ductile damage model for cyclic loading is found to be able to predict ductile crack growth behavior of structural component subjected to large cyclic deformation.